428 ANATOMICAL AND PATHOLOGICAL OBSEKVATIONS. 



solution ; and it involves a principle which serves to explain 

 many processes in health and disease, some of which have been 

 referred to in other parts of this work. 



I conclude, therefore, from the observations which I have 

 made — Is/, That all the true secretions are formed or selected 

 by a vital action of the nucleated ceil, and that they are first 

 contained in the cavity of that cell ; 2d, That growth and 

 secretion are identical — the same vital process, under different 

 circumstances.* 



* In Mr. Bowman's elaborate Paper "On tlie Structure and Use of the 

 Malpighian Bodies of the Kidney," read in the Royal Society of London, 17th 

 February 1842, and in his Ai'ticle " Mucous Membrane," in the Cydopcedia of 

 Anatomy, written in December 1841, certain parts of the tlieory of secretion 

 are well elucidated by a reference to human structiire. In my own Memoir, 

 read in the Eoyal Society of Edinburgh, 30th March 1842, I endeavoured, by 

 an appeal to facts in comparative anatomy, to establish secretion as a function 

 of the nucleated cell, and to show that glandular phenomena are only the 

 changes which the cellidar elements of these organs undergo. Mr. Bowman's 

 own observation on the secretion of fat by the cells of the human liver in a 

 state of disease was an important and positive result ; and Professor John 

 Eeid, with whom I had frequent conversations on the subject of secretion, and 

 to whom I had communicated my views on the subject a year before the 

 publication of my Paper, was in the habit of supporting Purkinje and Schwann's 

 hypothesis, by an appeal to the structure of Molluscum contagiosum, as de- 

 scribed by Professor Henderson and Dr. Paterson in the Edinburgh Medical 

 and Surgical Journal, 1841. 



